July 26 - August 1 (inclusive)
July 19th - 25th in 2009
The date of October 13, 2010 falls in the 41st week of the year.
January 1, 2011 was a Saturday. Counting from the 2nd, the start of the 30th week was July 24th.
October
It was 30th of December 1170. No difference if you assume that year 0 was in year 0.
It depends what year you're asking about. April 30th 2013 was a Tuesday.
30th MAY 1987
The 30th of December.
July 30th, 1980 fell on a Wednesday. The following year, it fell on a Thursday.
April 30th, 1803 fell on a Saturday. The following year, it fell on a Monday.
June 30th, 1952 fell on a Monday. The following year, it fell on a Tuesday.
June 30th, 1998 fell on a Tuesday. The following year, it fell on a Wednesday.